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Optimizer Problems
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I have a site along a ridgeline with multiple layers creating restrictions upon the layout. I've set each one up, tested each, and created a raster for the entire interpretation.
When I optimize the turbine positions, all works well until I take into account slope restrictions. We have a two-fold slope requirement - no turbines placed on slopes greater than 17 degrees, and a 24 meter setback from slopes greater than 30 degrees. For the 30-degree requirement, I created a shapefile of slopes more than 30 degrees and imported that, and gave it a setback of 24 meters.
Once either or both of those are taken into account, the optimizer doesn't seem to work as well--it places far fewer turbines than visually seems possible. For example, without the restriction, I can place 22 turbines. With the restriction, it goes down to a legal layout of 10--and I can visually see areas in the derived raster where turbines can be placed.
I experimented by making a shapefile of slopes more than 17 degrees, with the same result. I also experimented by making the DEM a parent of the site layer, instead of a child. This allowed me to add another turbine, even though the DEM layer had no validity setting.
The only thing I can think of is that the slope interpolation is making almost invisible areas where turbines cannot be placed. But I would think the shapefile option I tried would eliminate that. Another thought is that the area is too complicated for openWind to place turbines within. Other programs I've used have difficulty with complex boundaries.
I would be happy to upload the file for you to examine.
When I optimize the turbine positions, all works well until I take into account slope restrictions. We have a two-fold slope requirement - no turbines placed on slopes greater than 17 degrees, and a 24 meter setback from slopes greater than 30 degrees. For the 30-degree requirement, I created a shapefile of slopes more than 30 degrees and imported that, and gave it a setback of 24 meters.
Once either or both of those are taken into account, the optimizer doesn't seem to work as well--it places far fewer turbines than visually seems possible. For example, without the restriction, I can place 22 turbines. With the restriction, it goes down to a legal layout of 10--and I can visually see areas in the derived raster where turbines can be placed.
I experimented by making a shapefile of slopes more than 17 degrees, with the same result. I also experimented by making the DEM a parent of the site layer, instead of a child. This allowed me to add another turbine, even though the DEM layer had no validity setting.
The only thing I can think of is that the slope interpolation is making almost invisible areas where turbines cannot be placed. But I would think the shapefile option I tried would eliminate that. Another thought is that the area is too complicated for openWind to place turbines within. Other programs I've used have difficulty with complex boundaries.
I would be happy to upload the file for you to examine.
We've discovered a discrepancy between the grids used for the wrgs and the USGS 10-meter grid we're using in the model, but we're not sure that's causing the issue. To be on the safe side, we're remaking our grids. I also experimented using the default turbine types in openWind, since the model I was using was not completely filled out with the thrust curve, etc. But the results were the same.
I think I discovered part of the issue. I broke up the site into two projects. The wind roses are quite different for different parts of the site. I made a shapefile that encompassed all the restrictions and used that as my validity layer. I'll experiment and try the slope derivation again and see if I still have the same issue.
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